Question

A body moves a distance of $10\, m$ along a straight line under a action of $5\, N$ force. If work done is $25 \,J$, then angle between the force and direction of motion of the body will be

• A. $75^{\circ}$
• B. $60^{\circ}$
• C. $45^{\circ}$
• D. $30^{\circ}$

Answer 1

Answer: (B)

Distance $(s)=10 \,m$;
Force $(F)=5 N$ and work done $(W)=25 \,J$.
Work done $(W)=F s \cos \theta=25$
$\therefore 25=5 \times 10 \cos \theta=50 \cos \theta$
or $\cos \theta=25 / 50=0.5$
or $\theta=60^{\circ}$.